For the purpose of obtaining sunglass lenses and polarized spectacle lenses having high contrast properties, in general, it is known to use a resin lens having anti-glare and high contrast properties, which is made of a polyurethane resin or an allyl diglycol carbonate resin into which an organic light-absorbing pigment capable of absorbing light having a wavelength within the range of from 560 to 610 nm, such as tetraazaporphyrin, is uniformly incorporated (see, the below-identified Patent Document 1, for example).
In the resin lens as described above, the functional organic light-absorbing pigment is dispersed and retained uniformly throughout the entire lens. Therefore, when the thickness of the lens is adjusted by machining and polishing in order to adjust the power of the lens, the function of the lens is altered depending on the adjusted thickness of the lens, resulting in a failure to provide a uniform effect throughout the entire lens. Further, since a portion of the functional pigment is removed due to the machine processing of the lens, it has been unable to effectively and efficiently utilize the functional pigment.
In the case of a flat lens which does not require machine processing, the pigments used in the production thereof will not be wasted, even when a plurality of types of functional pigments are used in combination. In the case of a semi-lens (also referred to as a semi-finished lens) in which the adjustment of the lens power by machining is intended, on the other hand, the proportion of the functional pigments mixed in the resin lens to be wasted as machining chips is increased, leading to a problem of low utilization efficiency of valuable pigments.
In order to address the above mentioned problems, the use of a means to form one layer of functional film on the surface of a lens is also known.
For example, it is known to form a coating film by spin coating, when forming a functional film such as a hard coat or a polarizing film by applying a coating liquid on a lens substrate, in order to prevent the occurrence of an interference fringe due to uneven film thickness of the functional film (see the below-identified Patent Document 2).
Further, it is also known to form a coating film containing a photochromic pigment on the surface of a lens by a spin coating method (see the below-identified Patent Document 3).